My recommendation is to never get an alignment unless YOU detect a problem. As long as your tires wear evenly and last as long as you expected them to last, the alignment is good. Even potholes do not throw off an alignment although hitting a curb hard at an angle might.
If you have components that affect the alignment replaced, i.e ball joints, tie rods, bushings etc, then you will have to have an alignment when that work is done.
I do not trust “alignment checks” either. Sears and NTW (?) used to do “free” alignment checks with every set of tires purchased, All cars needed alignments. My wife fell for that while I was on a cruise (Navy), the OEM tires lasted 80k miles, the upgraded replacements from Sears with an alignment only lasted 20k.
My daughter also fell for that at NTW, I took the car back immediately and had them check again, they got completely different readings, same store different rack, then I took it to another NTW and got a third set of readings that did not match the first two. Then I had it aligned properly by a reputable mechanic.